The present invention relates to an aqueous system based on a biocide and on a polyorganosiloxane containing polyether functions, as well as to its use for the long-lasting disinfection of hard surfaces by slow, gradual release of the said biocide after application, by contact with water on the treated surface.
Aqueous biocidal compositions for treating hard surfaces generally have the drawback of rapidly losing their efficacy after they have been applied, in particular when the surfaces treated are then washed.
To overcome this drawback, it has been proposed to use film-forming organic polymers in these compositions in order to form, after application, a physical barrier which prevents the biocide from being released too quickly.
It has thus been suggested (WO 97/06675 from Rhxc3x4ne-Poulenc Chemicals Ltd.) to combine with a biocide a terephthalic copolyester having polyoxyethylene or polyoxyethylene terephthalate units in its polymer chain.
The Applicant has found a high-performance aqueous biocidal system.
A first subject of the invention is an aqueous biocidal system comprising
at least one water-soluble or water-dispersible biocidal agent, and
at least one polyorganosiloxane containing water-soluble or water-dispersible polyether functions, of formula (I)
R1R2R3SiO(R4R5SiO)p(R6QSiO)qSiR3R2R1xe2x80x83xe2x80x83(I)
in which formula
the symbols R1, R2, R4, R5 and R6, which may be identical or different, represent a phenyl or a C1 to C6 alkyl radical, preferably methyl,
the symbols R3, which may be identical or different, represent
a phenyl or C1 to C6 alkyl radical, preferably methyl,
or the symbol Q,
the symbol Q represents a polyoxyalkylene ether residue of formula
xe2x80x94Rxe2x80x94Oxe2x80x94(Rxe2x80x2O)nRxe2x80x3
where
R represents
a linear C3 to C15, preferably C3 to C10, alkyl group, most particularly trimethylene,
a branched C4 to C15, preferably C4 to C10, alkyl group, most particularly 2-methyltrimethylene,
the unit (Rxe2x80x2O)n represents a poly(ethylenoxy) and/or poly(propylenoxy) group,
n is an average value ranging from 5 to 200, preferably from 5 to 100
Rxe2x80x3 represents H or a C1 to C6, preferably C1, alkyl group
p is an average value ranging from 10 to 200, preferably from 10 to 100
q is
a value q1 equal to 0, R3 in this case representing the symbol Q
or, preferably, an average value q2 ranging from 1 to 100, preferably from 5 to 50, irrespective of R3.
It has been observed, advantageously, that the polyorganosiloxane structure of the polymer of formula (I) not only allows adhesion and wetting of the biocidal system to the support to be treated, but also creates a preferential interaction between the biocide and the polyether functions, by virtue of the high mobility of the polyorganosiloxane skeleton due to the low glass transition temperature of the polymer (Tg less than room temperature).
Among the biocidal agents which may be present in the said system of the invention, mention may be made of cationic, amphoteric, amino, phenolic and halogen-containing biocides. Systems based on cationic biocides are particularly advantageous.
As examples of biocides, mention may be made of:
cationic biocides such as quaternary monoammonium salts such as
cocoalkylbenzyldimethylammonium, C12-C14alkyl-benzyldimethylammonium, cocoalkyldichlorobenzyl-dimethylammonium, tetradecylbenzyldimethylammonium, didecyldimethylammonium and dioctyldimethylammonium chlorides
myristyltrimethylammonium and cetyltrimethyl-ammonium bromides
monoquaternary heterocyclic amine salts such as laurylpyridinium, cetylpyridinium and C12-C14alkyl-benzylimidazolium chlorides
triphenylphosphonium fatty alkyl salts such as myristyltriphenylphosphonium bromide
polymeric biocides such as those derived from the reaction
of epichlorohydrin and of dimethylamine or diethylamine
of epichlorohydrin and of imidazole
of 1,3-dichloro-2-propanol and of dimethylamine
of 1,3-dichloro-2-propanol and of 1,3-bis(dimethylamino)-2-propanol
of ethylene dichloride and of 1,3-bis(dimethylamino)-2-propanol
of bis(2-chloroethyl)ether and of N,Nxe2x80x2-bis(dimethylaminopropyl)urea or -thiourea
biguanidine polymer hydrochlorides, such as Vantocil IB
amphoteric biocides such as derivatives of N-(Nxe2x80x2-C8-C18alkyl-3-aminopropyl)glycine, of Nxe2x80x94(Nxe2x80x2xe2x80x94(Nxe2x80x3xe2x80x94C8-C18alkyl-2-aminoethyl)-2-aminoethyl)glycine, of N,N-bis(Nxe2x80x2xe2x80x94C8-C18-alkyl-2-aminoethyl)glycine, such as (dodecyl) (aminopropyl) glycine and (dodecyl) (diethylenediamine) glycine
amines such as N-(3-aminopropyl)-N-dodecyl-1,3-propanediamine
phenolic biocides such as para-chloro-meta-xylenol, dichloro-meta-xylenol, phenol, cresols, resorcinol, resorcinol monoacetate, and their derivatives or water-soluble salts
halogenated biocides such as iodophores and hypochlorite salts, such as sodium dichloroisocyanurate
Among the polyorganosiloxanes containing polyether functions which can be used in the system of the invention, mention may be made most particularly of those of formulae
Me3SiO(SiMe2O)x(SiMeQ1O)ySiMe3
and
Me2Q1SiO(SiMe2O)x(SiMeQ1O)ySiQ1Me2
in which formulae
x is an average value ranging from 10 to 200, preferably from 10 to 100,
y is an average value ranging from 1 to 100, preferably from 5 to 50
Q1 represents the radical
xe2x80x94(CH2)3O(CH2CH2O)z(CH2CH(CH3)Oz,H
or
xe2x80x94(CH2)3O(CH2CH2O)z(CH(CH3)CH2O)z,H
z is an average value ranging from 5 to 200, preferably from 5 to 100
zxe2x80x2 is an average value ranging from 0 to 100, preferably from 0 to 50 with z and zxe2x80x2ranging from 5 to 200, preferably from 5 to 100.
The biocidal agent and the polyorganosiloxane containing polyether functions represent the main constituents of the aqueous biocidal system forming the subject of the invention.
The biocide is preferably present in the aqueous biocidal system at a concentration of about 0.1% to 20% by weight, preferably of about 0.5% to 5% by weight.
The polyorganosiloxane containing polyether functions of formula (I) is preferably present in the aqueous biocidal system at a concentration of about 0.01% to 20% by weight, preferably of about 0.05 to 5% by weight.
The relative amounts of biocide and of polyorganosiloxane containing polyether functions can correspond to a biocide/polyorganosiloxane containing ether functionality weight ratio of about 0.1 to 50, preferably of about 0.5 to 25.
A first specific embodiment of the invention consists of an aqueous biocidal system in the form of an aqueous solution, in which system the biocidal agent and the polyorganosiloxane containing polyether functions are water-soluble.
According to the invention, along with the biocide and the polyorganosiloxane containing polyether functions, the main constituents of the aqueous biocidal system of the invention, other constituents, such as surfactants, chelating agents (such as aminocarboxylates, (ethylenediaminetetra-acetates, nitrilotriacetates, N,N-bis(carboxymethyl)-glutamates, citrates), alcohols (ethanol, isopropanol, glycols), detergency adjuvants (phosphates, silicates), dyes, fragrances, etc., may advantageously be present.
A second specific embodiment of the invention consists of a biocidal system containing, besides the biocide and the polyorganosiloxane containing polyether functions, at least one surfactant, particularly a nonionic, amphoteric, zwitterionic or anionic surfactant; these may be present in a proportion of from 1 to 25%, preferably from about 2 to 10%, of the weight of the said aqueous biocidal system.
Among the surfactants which may be present, mention may be made in particular of:
nonionic surfactants such as ethylene oxide/propylene oxide block polymers, polyethoxylated sorbitan esters, fatty esters of sorbitan, ethoxylated fatty esters (containing from 1 to 25 units of ethylene oxide), polyethoxylated C8-C22 alcohols (containing from 1 to 25 units of ethylene oxide), polyethoxylated C6-C22 alkylphenols (containing from 5 to 25 units of ethylene oxide), alkylpolyglycosides, amine oxides (such as C10-C18alkyldimethylamine oxides, C8-C22alkoxyethyldihydroxyethylamine oxides)
amphoteric or zwitterionic surfactants such as C6-C20alkylamphoacetates or amphodiacetates (such as cocoamphoacetates), C10-C18alkyldimethylbetaines, C10-C18-alkylamidopropyldimethylbetaines, C10-C18alkyldimethylsulphobetaines, C10-C18alkylamidopropyldimethyl-sulphobetaines.
One preferred form of this second specific embodiment consists of an aqueous biocidal system comprising:
at least one cationic, amphoteric or amino biocide, preferably a cationic biocide,
at least one polyorganosiloxane containing polyether functions, of formula (I), and
at least one nonionic, amphoteric or zwitterionic surfactant, preferably a nonionic surfactant.
Most preferably, the said system is in the form of an aqueous solution.
A second subject of the invention consists in using the biocidal system as described above for the disinfection of hard surfaces, or in a process for the disinfection of hard surfaces by using the said system.
The said system may be used to disinfect floors, walls, work surfaces, equipment, furniture, instruments, etc., in industry, in the agrifoods sector, in the domestic sectors (kitchens, bathrooms, etc.) and in combination.
Among the surfaces which can be treated, mention may be made of those made of ceramic, glass, polyvinyl chloride, formica or other hard organic polymer, stainless steel, aluminium, wood, etc.
The disinfection operation consists in applying the said biocidal system, which may have been diluted 1- to 1000-fold, preferably 1- to 100-fold, to the hard surface to be treated.
The amount of biocidal system which can favourably be used is that corresponding to an application of 0.01 to 10 g, preferably of 0.1 to 1 g, of biocide per m2 of surface and to an application of from 0.001 to 2 g, preferably from 0.01 to 0.5 g, of polyorganosiloxane containing polyether functions per m2 of surface.
After applying and drying the aqueous biocidal system on the hard surface, the biocidal agent in the system acts by controlled release when the treated surface is made wet with water or with aqueous soiling. This availability of the biocidal agent is limited to the volume of water or of aqueous medium in contact with it.
The biocidal system has the advantage of remaining active after the surface on which it has been applied has been washed a large number of times.
A third subject of the invention consists of the use, in an aqueous biocidal system for disinfecting a hard surface comprising-at least one water-soluble or water-dispersible biocidal agent, of at least one polyorganosiloxane containing water-soluble or water-dispersible polyether functions, of formula (I) above, as an agent for interacting with the said biocide for the controlled release of this biocide during contact with an aqueous medium (water or an aqueous soiling material, in particular) of the said hard surface onto which the said aqueous system has been applied and dried.
A final subject of the invention consists of a process for disinfecting a hard surface by controlled release of at least one water-soluble or water-dispersible biocidal agent during contact with an aqueous medium (water or an aqueous soiling material, in particular) of the said hard surface onto which an aqueous system has previously been applied and dried, this aqueous system comprising at least one water-soluble or water-dispersible biocidal agent and at least one polyorganosiloxane containing water-soluble or water-dispersible polyether functions, of formula (I) above, which interact with the said biocidal agent.
Among the microorganisms whose proliferation can be controlled using the biocidal system of the invention, mention may be made of
Gram-negative bacteria such as: Pseudomonas aeruginosa; Escherichia coli; Proteus mirabilis 
Gram-positive bacteria such as: Staphylococcus aureus; Streptococcus faecium 
other dangerous bacteria in food, such as: Salmonella typhimurium; Listeria monocytogenes; Campylobacter jejuni; Yersinia enterocolitica 
yeasts such as: Saccharomyces cerevisiae; Candida albicans 
fungi such as: Aspergillus niger; Fusarium solani; Pencillium chrysogenum 
algae such as: Chlorella saccharophilia; Chlorella emersonii; Chlorella vulgaris; Chlamydomonas eugametos 
The biocidal system of the invention is most particularly effective on the Gram-negative microorganism Pseudomonas aeruginosa, the Gram-positive microorganism Staphylococcus aureus, and the fungus Aspergillus niger.